High-speed near-infrared to RS485 communication system

Abstract

A high-speed near-infrared RS485 communication system, the system includes master control equipment and infrared-RS485 conversion slave equipment, the master control equipment and infrared-RS485 conversion slave equipment between through near-infrared communication mode carries out wireless communication, the infrared-RS485 conversion slave equipment and the external power supporting equipment with RS485 interface are connected.The present application realizes the conversion of near-infrared communication and RS485 under the condition of guaranteeing that the structure of electric meter meets IP54, and increases the near-infrared communication rate to 921.6KHz, without additional timer circuit to control the receiving and transmitting of RS485 interface chip separately, realizes the synchronous conversion of infrared signal and RS485 signal with low-cost circuit, is convenient for customer operation, is safer and has more cost advantage.

Description

Technical Field

[0001] This invention relates to the field of communication technology in power equipment application systems, and more specifically, to an application circuit that allows for the conversion between 921.6KHz high-speed infrared and RS485 communication methods within the same system. Background Technology

[0002] Currently, communication methods in the smart meter field are divided into many types based on different application scenarios and customer needs. For example, wired communication includes RS485, RS232, and PLC carrier, while wireless communication includes infrared transceiver, GPRS, LTE, and WiFi. Each of these communication methods has its own advantages and disadvantages. Among them, infrared communication is widely used in electricity meter equipment because of its low cost, simple communication method, and ability to meet the strict dustproof, waterproof, and lightning protection requirements of electricity meters. The disadvantages of infrared communication are short communication distance, low communication speed, and limited compatibility with external communication devices with corresponding interfaces. Currently, most power-related equipment on the market, such as meter reading terminals, computers, etc., have RS485 communication interfaces, and RS485 communication distance is relatively long, reaching several hundred meters. Considering factors such as cost and safety regulations, the interactive communication technology between high-speed near-infrared communication and RS485 in smart meter systems is highly practical and urgently needs to be solved. Summary of the Invention

[0003] This invention addresses the technical problem of interactive communication between high-speed near-infrared communication and RS485 in the same smart meter system, proposing a high-speed near-infrared to RS485 communication system; it realizes the communication conversion between 921.6KHz high-speed infrared and RS485, overcoming the difficulties of low speed of traditional near-infrared communication and high cost of infrared to RS485 communication.

[0004] The technical solution of this invention is:

[0005] A high-speed near-infrared to RS485 communication system is disclosed. The system includes a master control device and an infrared-to-RS485 conversion slave device. The master control device and the infrared-to-RS485 conversion slave device communicate wirelessly via near-infrared communication. The infrared-to-RS485 conversion slave device is connected to external power supply equipment with an RS485 interface.

[0006] The main control device includes a main control unit, a clock unit, a first signal amplification and shaping unit, a first infrared receiving unit, and a first infrared transmitting unit. The first infrared receiving unit of the main control device is connected to the infrared signal receiving end of the main control unit through the first signal amplification and shaping unit. The signal receiving end and the clock unit of the first infrared transmitting unit are respectively connected to the corresponding signal ends of the main control unit.

[0007] The infrared-RS485 conversion slave device includes a second infrared receiving unit, a second infrared transmitting unit, a second signal amplification and shaping unit, an RS485 level conversion unit, and an external interface / power supply unit. The second infrared receiving unit of the infrared-RS485 conversion slave device is connected to the infrared signal receiving end of the RS485 level conversion unit through the second signal amplification and shaping unit. The signal receiving end of the second infrared transmitting unit and the external interface / power supply unit are connected to the corresponding signal end of the RS485 level conversion unit. The external interface / power supply unit is connected to external power supply equipment with an RS485 interface.

[0008] Furthermore, the main control unit includes a microcontroller U1, resistors R1, R2, and R3, and a capacitor C1; one end of resistors R1, R2, and R3 is connected to pins 78, 79, and 80 of the microcontroller U1, and the other end of resistors R1, R2, and R3 is connected to power supply VDD1; one end of capacitor C1 is connected to reference ground GND1, and the other end is connected to the intersection of the non-power supply terminal of R3 and pin 80 of U1; pin 24 of the microcontroller U1 is connected to the IRXD terminal of the first infrared receiving unit; pin 25 of the microcontroller U1 is connected to the IRTX signal terminal of the first infrared transmitting unit; and pins 60 and 61 of the microcontroller U1 are connected to the clock unit.

[0009] Furthermore, the clock unit includes a crystal oscillator X1, a capacitor C4, and a capacitor C5; one end of capacitor C4 is connected to pin 1 of crystal oscillator X1, and the intersection of the two is connected to pin 60 of microcontroller U1; one end of capacitor C5 is connected to pin 2 of crystal oscillator X1, and the intersection of the two is connected to pin 61 of microcontroller U1; the other ends of capacitors C4 and C5, as well as pin 0 of crystal oscillator X1, are connected to reference ground GND1.

[0010] Furthermore, the first infrared emitting unit includes a resistor R5 and a diode D2; the diode D2 is an infrared emitting diode with a wavelength of 850nm, the positive terminal of the diode D2 is connected in series with one end of the resistor R5, and the negative terminal of the diode D2 is connected to pin 25 of the microcontroller U1 through the signal line IRTX; the other end of the resistor R5 is connected to the power supply VDD1.

[0011] Furthermore, the first infrared receiving unit includes a resistor R8 and a diode D1; the diode D1 is an infrared receiving diode, and has the highest sensitivity for receiving light in the 850nm band. The positive terminal of the diode D1 is connected to one end of the resistor R8, and the negative terminal of the diode D1 is connected to the power supply VDD1; the other end of the resistor R8 is connected to the reference ground GND1, and the connection point between the diode D1 and the resistor R1 outputs the infrared receiving signal IR1.

[0012] Further, the first signal amplification and shaping unit includes an operational amplifier U3, a comparator U2, an NPN transistor Q1, and resistors R4, R6, R7, R9, R10, and R11; the infrared received signal IR1 is input to pin 3 of the operational amplifier U3; pin 5 of the operational amplifier U3 is connected to power supply VDD1, and pin 2 is connected to reference ground GND1; pin 1 of U3 is connected to one end of resistor R10, and the other end of R10 is connected in series with R11 to reference ground GND1; pin 4 of U3 is connected to the voltage divider node connected by resistors R10 and R11; U3 Pin 1 of the transistor is connected to the base of transistor Q1 through resistor R9. The collector output of Q1 is connected to pin 2 of comparator U2 through resistor R7. At the same time, the collector output of Q1 is also connected to power supply VDD1 through resistor R6. The emitter of transistor Q1 is directly connected to reference ground GND1. Pin 1 of comparator U2 is connected to power supply VDD1 through resistor R4. Pin 5 of U2 is directly connected to power supply VDD1. Pin 3 of U2 is directly connected to reference ground GND1. Pin 4 of U2 is connected to pin 24 of microcontroller U1 of the main control unit through signal line IRRXD.

[0013] Furthermore, the second infrared emitting unit includes a resistor R22 and a diode D5; the diode D5 is an infrared emitting diode with a wavelength of 850nm, the positive terminal of the diode D5 is directly connected to the power supply VDD2, and the negative terminal of the diode D5 is connected to one end of the resistor R22; the other end of the resistor R22 is connected to the first pin of the communication interface chip U6 in the RS485 level conversion unit.

[0014] Furthermore, the second infrared receiving unit includes a resistor R25 and a diode D3; the diode D3 is an infrared receiving diode, and has the highest sensitivity for receiving light in the 850nm band. The positive terminal of the diode D3 is connected to one end of the resistor R25, and the negative terminal of the diode D3 is connected to the power supply VDD2; the other end of the resistor R25 is connected to the reference ground GND2, and the connection point between the diode D3 and the resistor R25 outputs the infrared receiving signal IR2.

[0015] Furthermore, the second signal amplification and shaping unit includes an operational amplifier U5, a comparator U4, dual NPN transistors Q3A and Q3B, dual PNP transistors Q2A and Q2B, resistors R13, R14, R15, R16, R17, R18, R19, R20, R21, R23, and R26, and capacitors C6, C9, and C10; the infrared receiving signal IR2 is input to pin 3 of the operational amplifier U5; pin 5 of the operational amplifier U5 is connected to power supply VDD2, and pin 2 is connected to reference ground GND2; Pin 1 of U5 is connected to one end of resistor R23, and the other end of R23 is connected in series with R26 to reference ground GND2; pin 4 of U5 is connected to the voltage divider node connected by resistors R23 and R26; pin 1 of U5 is connected to the base of transistor Q3A through resistor R20, and the collector output of Q3A is connected to pin 2 of comparator U4 through resistor R18. Simultaneously, the collector output of Q3A is also connected to power supply VDD2 through resistor R17; the emitter of transistor Q3A is directly connected to reference ground GND2; pin 1 of comparator U4... U4 is connected to power supply VDD2 via resistor R14. Pin 5 of U4 is directly connected to power supply VDD2, and pin 3 of U4 is directly connected to reference ground GND2. The output signal of pin 4 of U4 is split into two paths: one path is directly connected to pin 4 of the communication interface chip U6 in the RS485 level conversion unit; the other path is connected to the base of transistor Q2A via resistor R13, capacitor C6 is connected in parallel across resistor R13, the emitter of transistor Q2A is directly connected to power supply VDD2, and the collector output of transistor Q2A is connected to... Connect the base of transistor Q3B, C9 is connected in parallel across R15, and C10 is connected between the collector and base of transistor Q3B. The collector output of transistor Q3B is connected to the base of transistor Q2B through R19. At the same time, the base of Q2B is connected to power supply VDD2 through resistor R16. The emitter of transistor Q2B is directly connected to power supply VDD2. The collector of transistor Q2B is connected to reference ground GND2 through resistor R21. At the same time, the collector output of Q2B is connected to pin 2 of communication interface chip U6 in RS485 level conversion unit.

[0016] Furthermore, the RS485 level conversion unit includes a communication interface chip U6 and resistors R24 and R27; pin 1 of the communication interface chip U6 is connected to R22 in the second infrared emitting unit; pins 2 and 3 of U6 are connected together to the collector of transistor Q2B in the second signal amplification and shaping unit; pin 4 of U6 is connected to pin 4 of comparator U4 in the second signal amplification and shaping unit; pin 5 of the communication interface chip U6 is directly connected to reference ground GND2; pin 6 of U6 is connected to power supply VDD2 through resistor R24, and is also connected to pin 1 of external interface and power supply unit J1; pin 7 of U6 is connected to reference ground GND2 through resistor R27, and is also connected to pin 2 of external interface and power supply unit J1; pin 8 of U6 is directly connected to power supply VDD2.

[0017] Advantages and benefits of the present invention:

[0018] This invention achieves the conversion between near-infrared communication and RS485 while ensuring that the meter structure meets IP54 standards. It also increases the near-infrared communication rate to 921.6KHz and eliminates the need for additional timers or other circuits to separately control the RS485 interface chip's transmission and reception. This low-cost circuit enables synchronous conversion between infrared and RS485 signals, making it easier for customers to operate, safer, and more cost-effective. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a high-speed near-infrared to RS485 communication system according to the present invention.

[0020] Figure 2 This is a circuit diagram of the main control unit and clock unit of the main control device in this invention.

[0021] Figure 3 This is a circuit diagram of the first infrared receiving unit, the first infrared transmitting unit, and the first signal amplification and shaping unit of the main control device in this invention.

[0022] Figure 4 This is a circuit diagram of the second infrared receiving unit, the second infrared transmitting unit, the second signal amplification and shaping unit, and the RS485 level conversion unit of the infrared-RS485 conversion slave device in this invention.

[0023] Figure 5 This is a circuit diagram of the external interface and power supply unit of the infrared-RS485 conversion slave device in this invention.

[0024] Figure 6 This is one of the reference drawings showing the working mode and state of the communication interface chip U6 in this invention.

[0025] Figure 7The second attached figure shows the working mode and state of the communication interface chip U6 in this invention. Detailed Implementation

[0026] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0027] like Figure 1 As shown, this invention provides a high-speed near-infrared to RS485 communication system, consisting of a master control device and an infrared-to-RS485 conversion slave device. The infrared-to-RS485 conversion slave device serves as both an external interface and power supply unit, and its RS485 level conversion unit is responsible for communicating with external power equipment (such as standard consoles, terminals, computers, etc.) that have RS485 interfaces according to the RS485 standard protocol. Simultaneously, it converts the RS485 level to TTL level, which is then amplified and shaped by a signal amplification and shaping unit, followed by an infrared receiving unit and an infrared transmitting unit, before exchanging information with the master control device. This allows communication with external power equipment with RS-485 standard interfaces via the slave device, while ensuring the integrity of the master control device (i.e., the smart meter) casing.

[0028] like Figure 2 As shown, the main control unit of the main control device uses a low-power, high-capacity smart meter-specific microcontroller with a Cortex-M0+ core, a maximum of 512KB FLASH program memory, a maximum of 64KB SRAM, and integrated rich peripheral resources. In this design, it serves as the system master controller, communicating with the infrared transceiver unit and the infrared-RS485 conversion slave device via a serial port to exchange relevant information within the meter. The clock unit provides the clock frequency required for the operation of the infrared transceiver unit.

[0029] like Figure 3 As shown, the infrared receiver D1 on the main control device side conducts after receiving the infrared light signal emitted by the infrared emitting unit on the device side via infrared-RS485 conversion. Current flows through R8, generating a voltage drop. This voltage drop is amplified by operational amplifier U3 and used to drive transistor Q1. R6 is a pull-up resistor. The IRRXD port is normally high. When a near-infrared light signal is received, transistor Q1 conducts, and the IRRXD port goes low, thus completing the level conversion. Because there is a certain delay in the switching states of diode D1 and transistor Q1 at 921600 RPM, a buffer comparator U2 is added at the output for waveform shaping.

[0030] like Figure 4As shown, the infrared-RS485 converter turns on after receiving the infrared light signal emitted by the infrared transmitting unit on the main control device side from the infrared receiver tube D3 in the device. Current flows through R25, generating a voltage drop. This voltage drop is amplified by operational amplifier U5 and used to drive transistor Q3A. R17 is a pull-up resistor. The output of pin 4 of the buffer comparator U4 is normally high. When a near-infrared light signal is received, Q3A turns on, and the output signal U4-O from pin 4 of U4 becomes low. The U4-O signal is split into two paths: one connects to pin 4 (DI) of the interface communication chip U6, and the other connects to pins 2 / 3 (RE / DE) of U6 via level conversion. When the interface communication chip U6 is in receive mode, the level state between the RE / DE and DI signals does not affect the normal operation of U6. When the interface communication chip U6 is in transmit mode, the RE / DE signal is high and the DI signal is low, and communication is normal. When the RE / DE signal is low and the DI signal is high, the U6 output is in a high-impedance state, and communication is abnormal. Therefore, to ensure normal communication and prevent the interface communication chip U6 from entering a high-impedance state, the RE / DE signal level transition needs to be delayed for a period of time. Therefore, the U4-O signal is used to control RE / DE. The U4-O signal has two states:

[0031] a. When there is data on U4-O (U4-O signal is low), the process of RE / DE being quickly set to high level is as follows:

[0032] U4-O is initially at a high level, so Q2A, Q3B, and Q2B are in the off state. Therefore, the RE / DE signal output from the collector of transistor Q2B is low. That is, when there is no signal from U4-O, RE / DE is low. R16 and R19 provide static bias for transistor Q2B, so that it is in the off state when there is no signal from U4-O. When U4-O changes from its initial state to a low level, Q2A turns on, followed by Q3B and Q2B in sequence, which is equivalent to a three-stage amplification, accelerating the transistor's conduction. The output RE / DE becomes high. C6 and C9 also play a role in accelerating the transistor's conduction. The principle is that when the U4-O signal is low, since the voltage on capacitor C6 cannot change abruptly, according to i = Cdu / dt, a large current will flow into the base, causing the transistor to quickly enter the saturation conduction state from the cutoff state. After the voltage on C6 stabilizes, the transistor is kept in the saturation conduction state. The acceleration effect of C9 is similar to that of C6. After acceleration, the input signal DI and RE / DE are kept synchronized. That is, when there is data on DI, RE / DE is quickly set high.

[0033] b. When there is no data in U4-O (U4-O signal is high), the process of delaying RE / DE to low level:

[0034] When there is no data in U4-O, RE / DE needs to go low, so Q2B needs to go from the saturated conduction state to the cutoff state. When entering the cutoff state, some charge needs to be discharged through Q3B, and Q3B discharges through Q2A. Since Q2A enters the cutoff state before Q3B, and Q3B enters the cutoff state before Q2B, the transition of Q2B from the saturated conduction state to the cutoff state will be very slow. C10 also delays the turn-off time of Q2B, thus playing a certain delay role and ensuring that there are no communication abnormalities.

[0035] Reference Appendix for the Operating Modes and Status of Communication Interface Chip U6 Figure 6 , attached Figure 7 .

[0036] like Figure 5 As shown, the power supply section of the infrared-RS485 conversion slave device converts the power input VDD3 from the external interface J1 to VDD2 through the LDO chip U8 to power the internal circuit of the infrared-RS485 conversion slave device. D4 and R28 protect the LDO chip U8, and C13 provides more energy to the RS485 level conversion unit circuit to avoid pulling the signal level low and causing communication abnormalities when transmitting data. The J1 interface is used for information exchange with external power equipment with RS485 interface.

[0037] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A high-speed near-infrared to RS485 communication system, characterized in that: The system includes a master control device and an infrared-RS485 conversion slave device. The master control device and the infrared-RS485 conversion slave device communicate wirelessly via near-infrared communication. The infrared-RS485 conversion slave device is connected to external power supply equipment with an RS485 interface. The main control device includes a main control unit, a clock unit, a first signal amplification and shaping unit, a first infrared receiving unit, and a first infrared transmitting unit. The first infrared receiving unit of the main control device is connected to the infrared signal receiving end of the main control unit through the first signal amplification and shaping unit. The signal receiving end and the clock unit of the first infrared transmitting unit are respectively connected to the corresponding signal ends of the main control unit. The infrared-RS485 conversion slave device includes a second infrared receiving unit, a second infrared transmitting unit, a second signal amplification and shaping unit, an RS485 level conversion unit, and an external interface / power supply unit. The second infrared receiving unit of the infrared-RS485 conversion slave device is connected to the infrared signal receiving end of the RS485 level conversion unit through the second signal amplification and shaping unit. The signal receiving end of the second infrared transmitting unit and the external interface / power supply unit are connected to the corresponding signal end of the RS485 level conversion unit. The external interface / power supply unit is connected to external power supply equipment with an RS485 interface. The first infrared emitting unit includes a resistor R5 and a diode D2; the diode D2 is an infrared emitting diode with a wavelength of 850nm. The positive terminal of the diode D2 is connected in series with one end of the resistor R5, and the negative terminal of the diode D2 is connected to pin 25 of the microcontroller U1 through the signal line IRTX; the other end of the resistor R5 is connected to the power supply VDD1. The second infrared emitting unit includes a resistor R22 and a diode D5; the diode D5 is an infrared emitting diode with a wavelength of 850nm. The positive terminal of the diode D5 is directly connected to the power supply VDD2, and the negative terminal of the diode D5 is connected to one end of the resistor R22; the other end of the resistor R22 is connected to the first pin of the communication interface chip U6 in the RS485 level conversion unit. The second signal amplification and shaping unit includes an operational amplifier U5, a comparator U4, dual NPN transistors Q3A and Q3B, dual PNP transistors Q2A and Q2B, resistors R13, R14, R15, R16, R17, R18, R19, R20, R21, R23, and R26, and capacitors C6, C9, and C10. The infrared receiving signal IR2 is input to pin 3 of operational amplifier U5. Pin 5 of operational amplifier U5 is connected to power supply VDD2, and pin 2 is connected to reference ground GND2. Pin 1 of U5 is connected to one end of resistor R23, and the other end of R23... One end is connected in series with R26 to reference ground GND2; pin 4 of U5 is connected to the voltage divider node connected by resistors R23 and R26; pin 1 of U5 is connected to the base of transistor Q3A through resistor R20, the collector output of Q3A is connected to pin 2 of comparator U4 through resistor R18, and the collector output of Q3A is also connected to power supply VDD2 through resistor R17; the emitter of transistor Q3A is directly connected to reference ground GND2; pin 1 of comparator U4 is connected to power supply VDD2 through resistor R14, pin 5 of U4 is directly connected to power supply VDD2, and pin 3 of U4... The pin is directly connected to reference ground GND2. The output signal of pin 4 of U4 is divided into two paths. One path is directly connected to pin 4 of the communication interface chip U6 in the RS485 level conversion unit; the other path is connected to the base of transistor Q2A through resistor R13, with capacitor C6 connected in parallel across resistor R13. The emitter of transistor Q2A is directly connected to power supply VDD2. The collector output of transistor Q2A is connected to the base of transistor Q3B through resistor R15, with C9 connected in parallel across R15, and C10 connected across the collector and base of transistor Q3B. The collector output of transistor Q3B is connected through... R19 is connected to the base of transistor Q2B, and the base of Q2B is connected to power supply VDD2 through resistor R16. The emitter of transistor Q2B is directly connected to power supply VDD2, and the collector of transistor Q2B is connected to reference ground GND2 through resistor R21. The collector output of Q2B is connected to pin 2 of the communication interface chip U6 in the RS485 level conversion unit. The second signal amplification and shaping unit uses multiple transistors Q2A, Q2B, Q3A, Q3B and capacitors C6, C9, C10 to accelerate conduction and delay turn-off, ensuring synchronization with the RS485 level conversion unit.

2. The high-speed near-infrared to RS485 communication system according to claim 1, characterized in that: The main control unit includes a microcontroller U1, resistors R1, R2, and R3, and a capacitor C1. One end of resistors R1, R2, and R3 is connected to pins 78, 79, and 80 of the microcontroller U1, and the other end of resistors R1, R2, and R3 is connected to power supply VDD1. One end of capacitor C1 is connected to reference ground GND1, and the other end is connected to the intersection of the non-power supply terminal of R3 and pin 80 of U1. Pin 24 of the microcontroller U1 is connected to the IRXD terminal of the first infrared receiving unit. Pin 25 of the microcontroller U1 is connected to the IRTX signal terminal of the first infrared transmitting unit. Pins 60 and 61 of the microcontroller U1 are connected to the clock unit.

3. The high-speed near-infrared to RS485 communication system according to claim 1, characterized in that: The clock unit includes a crystal oscillator X1, a capacitor C4, and a capacitor C5; one end of capacitor C4 is connected to pin 1 of crystal oscillator X1, and the intersection of the two is connected to pin 60 of microcontroller U1; one end of capacitor C5 is connected to pin 2 of crystal oscillator X1, and the intersection of the two is connected to pin 61 of microcontroller U1; the other ends of capacitors C4 and C5, as well as pin 0 of crystal oscillator X1, are connected to reference ground GND1.

4. The high-speed near-infrared to RS485 communication system according to claim 1, characterized in that: The first infrared receiving unit includes a resistor R8 and a diode D1; the diode D1 is an infrared receiving diode, the positive terminal of the diode D1 is connected to one end of the resistor R8, and the negative terminal of the diode D1 is connected to the power supply VDD1; the other end of the resistor R8 is connected to the reference ground GND1, and the connection point of the diode D1 and the resistor R1 outputs the infrared receiving signal IR1.

5. The high-speed near-infrared to RS485 communication system according to claim 1, characterized in that: The first signal amplification and shaping unit includes an operational amplifier U3, a comparator U2, an NPN transistor Q1, and resistors R4, R6, R7, R9, R10, and R11; the infrared received signal IR1 is input to pin 3 of the operational amplifier U3; pin 5 of the operational amplifier U3 is connected to power supply VDD1, and pin 2 is connected to reference ground GND1; pin 1 of U3 is connected to one end of resistor R10, and the other end of R10 is connected in series with R11 to reference ground GND1; pin 4 of U3 is connected to the voltage divider node connected by resistors R10 and R11; pin 1 of U3... The pin is connected to the base of transistor Q1 through resistor R9. The collector output of Q1 is connected to pin 2 of comparator U2 through resistor R7. At the same time, the collector output of Q1 is also connected to power supply VDD1 through resistor R6. The emitter of transistor Q1 is directly connected to reference ground GND1. Pin 1 of comparator U2 is connected to power supply VDD1 through resistor R4. Pin 5 of U2 is directly connected to power supply VDD1. Pin 3 of U2 is directly connected to reference ground GND1. Pin 4 of U2 is connected to pin 24 of microcontroller U1 of the main control unit through signal line IRRXD.

6. The high-speed near-infrared to RS485 communication system according to claim 1, characterized in that: The second infrared receiving unit includes a resistor R25 and a diode D3; the diode D3 is an infrared receiving diode, the positive terminal of the diode D3 is connected to one end of the resistor R25, and the negative terminal of the diode D3 is connected to the power supply VDD2; the other end of the resistor R25 is connected to the reference ground GND2, and the connection point of the diode D3 and the resistor R25 outputs the infrared receiving signal IR2.

7. The high-speed near-infrared to RS485 communication system according to claim 1, characterized in that: The RS485 level conversion unit includes a communication interface chip U6 and resistors R24 and R27. Pin 1 of the communication interface chip U6 is connected to R22 in the second infrared emitting unit. Pins 2 and 3 of U6 are connected together to the collector of transistor Q2B in the second signal amplification and shaping unit. Pin 4 of U6 is connected to pin 4 of comparator U4 in the second signal amplification and shaping unit. Pin 5 of the communication interface chip U6 is directly connected to reference ground GND2. Pin 6 of U6 is connected to power supply VDD2 through resistor R24 ​​and is also connected to pin 1 of external interface and power supply unit J1. Pin 7 of U6 is connected to reference ground GND2 through resistor R27 and is also connected to pin 2 of external interface and power supply unit J1. Pin 8 of U6 is directly connected to power supply VDD2.

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